1. Field of the Invention
This invention relates to a method and system for expeditiously reducing noise from a flame.
2. Description of the Related Art
Unwanted acoustic sound has negative effects on humans and animals. Some of the negative effects of unwanted noise include damage to hearing, creating an inefficient work environment and inducing dangerous vibrations in buildings. Conventional methods for reducing the sound intensity of noise include passive and active noise control.
Prior art passive noise control systems include using sound absorbent materials around the source of the noise. The use of sound absorbent material has the disadvantage that the material is expensive and the material is ineffective for lower frequencies. In addition, passive noise control systems are not suitable for a flame environment.
Conventional active noise control systems attenuate undesirable noise in the form of acoustic waves by producing and superimposing noise canceling waves which are substantially equal in amplitude and frequency content, but shifted 180 degrees in phase with respect to the noise. A speaker produces the canceling waves or vibrations.
U.S. Pat No. 2,043,416 describes an active control system for silencing sound oscillations of sound waves travelling through the air. A microphone receives a sound wave travelling through the air in one direction. An amplifier connected to the microphone produces sound waves having opposite phase in relation to the received sound wave. The opposite phase sound waves travel in the same direction as the received sound waves to cause mutual elimination of the two sound waves.
U.S. Pat. No. 5,146,505 describes a method for actively attenuating engine generated noise. A signal is adaptively filtered to produce a canceling waveform which is superimposed with the engine noise to attenuate selected multiple harmonic noise components. The canceling waveform drives a speaker to generate canceling acoustic waves for superposition with the engine induction noise.
It is known that noise is produced by combustion gases in a high intensity flame. However, the inventor is unaware of any systems for accurately and quickly reducing noise produced from a flame.